Study On Design Method For Mainframe Of Hydraulic Press Considering Forming Precision Of Mouldings

Hydraulic press is fundamental to manufacturing industry. Though stiffness of hydraulic press has direct impact on the forming precision of mouldings, as there is less knowledge about the forming precision of mouldings versus the stiffness of hydraulic press, design indexes of the stiffness performance of hydraulic press are mainly determined by experience in current hydraulic press design, which may result in stiffness shortage and low forming precision of mouldings, or stiffness overage and high cost of the press. To resolve the above issue, a design method for mainframe of hydraulic press considering forming precision of mouldings is proposed and studied in this thesis. Main research works and results of the thesis are as follows.1. By analysis of the hydraulic press-mould system, it was concluded that the stiffness of lower beam of hydraulic press is the major factor affecting the forming precision of mouldings. And a mapping model between the forming precision of mouldings and the deflection of the lower beam is established, with which the forming precision of mouldings can be mapped to the design index of the lower beam stiffness.2. A method for conceptual design of mainframe of hydraulic press is constructed. The method consists of setting up mechanical models and conceptual design models of structural components of the mainframe with mechanics of material theory, designing the conceptual prototypes of the structural components by calculating initial moment of bending and cross section area of shearing of the structural components based on the conceptual design models according to the technical specifications and the design indexes of stiffness of the mainframe of the hydraulic press, and finally designing the structural prototype of the mainframe based on the conceptual prototypes. The structural prototype of the mainframe can be a starting point for optimization of the mainframe of hydraulic press.3. A sensitivity analysis and approximate modeling based strategy for mainframe optimization of hydraulic press is put forward. The optimization strategy includes two steps: step 1, stiffness and mass sensitivity analysis of the structural components with FEA (finite element analysis), by which key dimension parameters can be filtrated as candidates of optimization variables of the mainframe; step 2, setting up the approximate optimization model for the mainframe by means of DOE (design of experiments) and FEA with light weight or light weight and high stiffness as object of optimization, and solving the model by appropriate optimization algorithm to obtain optimized design schemes for the mainframe of hydraulic press.4. A design method for mainframe of hydraulic press considering forming precision of mouldings is proposed. In this method, the design process of the mainframe is as follows: firstly, the forming precision of mouldings is mapped to the design index of the lower beam stiffness via the mapping model between the forming precision of mouldings and the deflection of the lower beam; secondly, the conceptual prototype and structural prototype of the mainframe is designed with the conceptual design models of the structural components according to the technical specifications and the design indexes of stiffness of the mainframe; thirdly, the sensitivity analysis and optimization is carried out to acquire optimized design schemes of the mainframe of hydraulic press based on the structural prototype.5.The design method is applied to the mainframe design of Model THP10-10000 100MN isothermal forging hydraulic press. Conceptual prototype design, structural prototype design and optimization of the mainframe of the hydraulic press are realized by the method. Optimized design scheme for light weight and Pareto optimized design schemes for light weight and high stiffness are obtained of the mainframe of the hydraulic press. The light weight optimized design scheme provides a light weight rate of 2.044% and 5.774% in comparison with the structural prototype and the engineering mockup respectively while satisfying the design indexes of stiffness of the mainframe. The Pareto optimized design schemes for light weight and high stiffness provides multi feasible solutions for the mainframe of the hydraulic press.Although the object of this thesis is hydraulic press, the ideas and principles proposed in the thesis are applicable and general to the design of other forming equipment.